Onion Cultivation: Beginner’s Guide on Onion Farming

Onion cultivation is a very profitable business. Onion plant can be cultivated as a monocrop or intercrop. Here is the complete guidance on onion farming including onion growing conditions, season, seeds, diseases and harvesting.

Globally, China, India and US are the largest producers of onions with India being the second largest producer of onion. Indian onions have two crop cycles with the first onion harvesting during November to January months and second during January to May months. Hence, onion is available throughout the year in India.

Information on Onion

Botanical name for onion is Allium cepa– belonging to Liliaceae family. Its closest relatives are shallots, garlic and leeks. It is a bulbous plant with the bulbs being produced annually. The leaves are semi-cylindrical or tubular in structure. They have a waxy coating on the surface and emerge from a subterranean bulb that bears short, branched roots. The stem grows upto 200 cm in height. Flowers appear at the tip of the stem and are greenish-white in color. The bulb has several layers of overlapping surfaces around a central core and it can expand upto 10 cm in diameter.

Ideal Conditions for Onion Cultivation

Onion needs a temperate climate and alluvial soil to grow in. Depending on the onion growing time and place of cultivation, onion can be grown as long day onions (for plains) or short day onions (ideal for hilly regions).

Climate for Onion Farming

Although it is a temperate crop, onion cultivation can be possible under sub-tropical, temperate or tropical climate. A mild, gentle weather that is not too rainy, too cold or too hot is ideal for onion growing. However, it can withstand extreme weather conditions at younger stage. Short day onions that need 10-12 hours of day length are grown in plains while long day onions requiring 13-14 hours of day length are grown in the hilly areas.

Onion crops need lower temperature and shorter day light (photoperiod) for vegetative growth while during the bulb development and maturity stage it needs a higher temperature and longer day light. Other requirements for onion cultivation are:

Temperature	Vegetative phase- 13-24⁰C Bulb development phase- 16-25⁰C
Relative Humidity	70%
Average annual rainfall	650-750 mm

Season for Onion Farming

In India, onions are cultivated both as kharif and rabi crop. This is because onions are grown in almost all the Indian states. The time and season of onion cultivation depends on the geographical location and weather at the particular place. Here is a table containing the time of cultivation and harvesting in different places of cultivation in India:

Place	Season	Time of Sowing	Time of Harvest
Hilly Areas	Rabi	September- October	June- July
	Summer	November- December	August- October
Punjab, Haryana, UP, Bihar, Rajasthan	Kharif	June- July	October- November
	Rabi	October- November	May-June
Orissa and West Bengal	Kharif	June- July	November- December
	Late Kharif	August- September	February- March
	Rabi	September- October	March- April
Maharashtra and parts of Gujarat	Early Kharif	February- March	August- September
	Kharif	May- June	October- December
	Late Kharif	August- September	January- March
	Rabi	October- November	April- May
Andhra Pradesh, Tamil Nadu, Karnataka	Early Kharif	February- April	July- September
	Kharif	May- June	October- November
	Rabi	September- October	March- April

Soil for Onion Cultivation in India

Onions can be grown in all types of soils such as heavy soil, clayey soil, sandy loam, etc. However, red to black loamy soil with good drainage capacity is ideal for onion cultivation. The soil must be friable, have good moisture holding capacity as well as enough organic matter. Although onions can be grown in heavy soils it must have a good amount of organic matter. Hence applying manure (farm yard or poultry) at the time of field preparation in case of heavy soil onion cultivation is important. In addition, onions cannot survive in saline, acidic or alkaline soils.

pH for Onion Growing

Soil with neutral pH (6.0 to 7.0) is optimal for onion cultivation. It can tolerate mild alkalinity (pH upto 7.5). They cannot survive if the soil pH drops below 6.0 owing to aluminum or manganese toxicity or trace element deficiency.

Water for Growing Onions

Onion crop irrigation depends on the season of planting, type of soil, irrigation method and age of the crop. Generally, irrigation is done at the time of seedling plantation, during transplantation period, 3 days after transplantation and subsequently at regular intervals depending on the moisture content in soil. The last irrigation is done 10 days before harvesting onion. Being a shallow-rooted crop, onions need small amounts of irrigation at regular intervals. This helps maintain optimal soil temperature and moisture for growth and bulb development. Excess irrigation followed by dry spell would result in bolter formation and splitting of outer scales. Modern irrigation techniques like drip and sprinkler irrigation are used as they help prevent excess water loss. These techniques help maintain the ideal moisture level in soil. In addition, dispensing water through drip or sprinkler emitter would ensure water at the root of the plant. It prevents water seepage into the soil and thus water loss to a great extent.

Intercropping in Onion Cultivation

Onion being shallow-rooted is suitable for intercropping. In other words, two or more crops can be grown together. However it also depends on location, nature of soil and climatic conditions. The main idea of inter-cropping is to use the resources effectively and gain a great yield without causing any harm to the main crop. If onion is planted as rabi crop then it can be paired with sugarcane. For this, furrows and ridges are prepared for sugarcane. After two rows of sugarcane, a flatbed for onion is prepared. Both onion seedling and sugarcane is planted simultaneously. This type of planting under drip irrigation helps save 25-30% water.

Crop Rotation with Onion Farming

Being a shallow rooted crop efficient and optimal utilization of all the applied soil mineral nutrients is unlikely. The unused nutrients would leach down and settle in the sub-soil. In the next growing season, planting leguminous crops would ensure utilization of these nutrients. Thus, onion and legume cultivation sequence is recommended for maintaining soil health, optimum nutrient utilization and higher yield.

Planting Material for Onion Cultivation

Since cultivation of onion is influenced by a variety of factors like temperature, photoperiod, weather,  etc. research institutes have developed different varieties suitable for particular seasons and regions. The commercially grown variety is classified into 3 groups as White, Yellow and Red. Here is a list of different varieties developed by various research institutes:

White Varieties

Name of Variety	Centre to Develop	Characteristic	Yield (Quintal per Hectare)	Resistance	Season of Growth
Pusa White round	ICAR-IARI, New Delhi	Bulbs are white Round in shape and flat Suitable for dehydration	300
Pusa White flat	ICAR-IARI, New Delhi	Bulbs are white Flat Bulbs vary from medium to large Suitable for dehydration.
Bhima Shweta	ICAR-DOGR, Pune	Bulbs are white in color Round shaped bulbs Matures in 110-115 day after transplanting Can be stored upto 3 months	350	Tolerant to thrips	Rabi
Bhima Shubra	ICAR-DOGR, Pune	Bulbs are white in color Oval to round shaped bulbs Matures in 112-125 after transplantation Can be stored for 2-3 months	240 (Kharif) 380 (late Kharif)	Tolerant to environmental fluctuations	Kharif and Late Kharif
Agrifound White	NHRDF, Nasik	Bulbs are white Round in shape Good storage quality Matures in 160-165 days Suitable for dehydration	200-250
Punjab-48 (S-48)	PAU, Ludhiana	Bulbs are white Round and  flattish in shape The have a very good texture & flavor Good storage quality Suitable for dehydration
Punjab White	PAU, Ludhiana	Bulbs are large and round with a white neck Suitable for dehydration.	250-300
N-257-9-1	MPKVP, Rahuri	Bulbs are white They are globe-shaped Good storage quality Suitable for dehydration.			Rabi
Udaipur-102	MPUAT, Udaipur	Bulb is white They have round to flat shape Matures in 120 days	300-350

Yellow Color Varieties

Name	Centre	Characteristics	Yield (Quintal per hectare)	Resistance to	Season of Growth
Early Grano	ICAR- IARI, New Delhi	Bulbs are globe shaped They are less pungent Good storage quality Ideal for growth in hills	300-350
Brown Spanish	ICAR-IARI, Regional Station, Katrain	Thick-skinned bulbs Less pungent Medium long day variety Suitable for hilly areas Bulbs are thick skinned, less pungent	250-300q/ha.
Arka Pitamber	ICAR-IIHR, Bengaluru	Uniform, yellow colored, globe-shaped bulbs Short-day type. Good storage quality They are free from splits, bolters and internal doubles
Phule Swarna	MPKVP, Rahuri	Less pungent, They can be stored upto 4-6 months Exported to Europe, Australia and America.	240q/ha.

Red Color Varieties

Name of Variety	Center	Special Characteristics	Yield (quintal per hectare)	Resistance to	Season of Growth
Pusa Red	ICAR- IARI, New Delhi	Medium-sized, bronze-colored bulbs Globular or flat shape Average individual bulb weight 70-90g Less pungent Good storage quality Matures in 125-140 days after transplant.	250-300q/ha.
Pusa Ratnar	ICAR- IARI, New Delhi	Bulbs are globular, oblate to flat They are bronze to red colored They are larger in size Less pungent Fair in storage quality	300-400q/ha
Pusa Madhavi	ICAR-IARI, New Delhi	Bulbs medium to large Light red in color Flattish- round in shape Matures in 130-135 days after transplanting. Good storage quality	300q/ha.
Pusa Ridhi	ICAR-IARI, New Delhi	Bulbs are compact, flat globe- shaped They are dark red in color Individual bulb weight ranges from 70-100g Pungent Rich in antioxidant Well-suited for storage and export	310		Both kharif and rabi
Arka Pragati	ICAR-IIHR, Begaluru	Bulbs are pink colored and globe-shaped Bulbs produced are of uniform size Have a high pungency Grown successfully during rabi and kharif in the South. Matures early- within 140-145 days of transplanting.	200		Kharif and Rabi
Arka Niketan	ICAR-IIHR, Bengaluru	Globular bulbs Individual bulb weighs 100-180g High pungency Storage at room temperature upto 5 months Matures in 145 day.
Arka Kalyan		Globular bulbs with deep pink colored outer scales Fleshy succulent internal scales Individual bulbs weighs 100-190g	335	Purple blotch	Kharif
Arka Bindu	ICAR-IIHR, Bengaluru	Bulbs are small in size (2.5-3.5cm) They are deep pink in color Pungent Matures early Free from early bolting and splitting Exported to Malaysia to Singapore.	250
Bangalore Rose	ICAR-IIHR, Bengaluru	Bulbs are small in size They are uniform in color Suitable for export	150
Arka Lalima(F1)	ICAR-IIHR, Bengaluru	Hybrid quality Bulbs are deep red, with firm texture, Can be stored upto 5 months Can bear the  transport stress Free from split & bolters Matures in 130-135 days.	500	Biotic stress
Arka Kirtiman	ICAR-IIHR, Bengaluru	Hybrid variety producing red bulbs Firm texture Can be stored upto 5 months Good for transport, Matures in 120-125 days after transplantation Suited for Andhra Pradesh, Eastern Madhya Pradesh and Orissa.	300-375	Can withstand biotic stress
Bhima Raj	ICAR-DOGR, PUNE	Produces dark red bulbs They are oval shaped Matures within 120-125 days after Can be stored up to 3 months if planted in rabi	250-300		Rabi
Bhima Red	ICAR-DOGR, PUNE	Red colored, round shaped bulbs. Matures in 115-120 days after transplanting	480-520		Kharif Late Kharif Rabi (must be immediately marketed)
Bhima Super	ICAR-DOGR, PUNE	Bulbs are medium- sized, red colored and The bulbs produced are single-centered Matures after 100-110 days after transplanting	260-280 during kharif and 400-450 during late kharif		Kharif Late kharif
Bhima Kiran	ICAR-DOGR, PUNE	Immediately upon harvesting, the bulbs attain light red color They are oval to round- shaped Can be stored up to 5-6 months Matures in 130 days after transplanting	410		Rabi
Bhima Shakti	ICAR-DOGR, PUNE	Bulbs turn red in color immediately after harvesting They are round shaped They can be stored upto 6 months Mature in 130 days after transplanting	420-450	Thrips	Late kharif and rabi

Land Preparation for Onion Farming

Onion can grow in almost all types of soils. Generally, the seeds are sowed in nursery and the seedlings are transplanted after approximately 30-40 days. Before transplantation the field must be ploughed properly to get rid of the soil clods and unwanted debris. Vermicomposting (approximately 3 tonnes per acre) or poultry manure can be incorporated. This is done during the last ploughing.

After ploughing the fields are levelled and beds are prepared. Depending on the season, the beds maybe flat beds or broad bed furrows. Flat beds are 1.5-2 meter in width and 4-6 meter in length. Broad bed furrows have a height of 15 cm and top width of 120 cm. The furrows are 45 cm deep so as to get the right spacing. Onions are cultivated in broad bed furrows during kharif season since it is easier for excess water to drain out through the furrows. It also facilitates aeration and reduces occurrence of Anthracnose disease. Flat beds are made if onion cultivation is done during rabi season. Flat beds for kharif can cause water logging.

Planting Onion

Onion seeds are first sown in nurseries and later transplanted to the open fields. Nursery management and transplanting are hence the most important steps in onion cultivation.

Nursery Management

For one acre of onion plantation, seedlings can be prepared in 0.12 acre of area. The nursery field must be ploughed well and made free of clods. The soil must be reduced to finer particles so as to hold enough water. The filed must be clear of stones, debris and weeds. Just like the main field preparation, farm yard manure (half ton) must be applied at the time of last ploughing. Raised beds are recommended for nursery preparation. This is because flat beds allow water movement from end to end. There is a risk of seeds getting washed away in the process. The beds must be raised to a height of 10-15 cm, width of 1 m and length as per convenience. Keep a distance of at least 30 cm between the beds to allow easy drainage of excess water. 0.2% Pendimethalin is used for controlling the weeds in the nursery. 2-4 Kg of seeds is required for one acre of onion cultivation.

Seed Preparation

Seeds are treated with 2g/Kg of thiram or Trichoderma viride to prevent damage from damping off diseases. The seed distance is maintained at 50-75mm to facilitate easy weeding and removal of seedlings for transplantation. The seeds are covered with farm yard manure after sowing and watered slightly.

Transplantation

Onion seeds are first grown in nurseries and then the seedlings are transplanted to the fields 30-40 days later. 3-4 Kg seeds are needed for one acre of field. Early transplantation yields more bulbs. During transplantation, care must be taken to avoid over and under-aged seedlings. The following process is followed during transplantation:

• About one-third of the top of the seedling is cut
• Roots are dipped in 0.1% carbendazim solution for two hours to prevent fungal diseases
• The seedlings are transplanted into prepared beds at a distance of 10 cm between plants.

The transplantation schedules for onion crop at different locations are as below:

Place	Season	Time of Sowing	Time of Transplantation
Hilly Areas	Rabi	September- October	October- November
	Summer	November- December	February- March
Punjab, Haryana, UP, Bihar, Rajasthan	Kharif	June- July	July- August
	Rabi	October- November	December- January
Orissa and West Bengal	Kharif	June- July	August- September
	Late Kharif	August- September	October- November
	Rabi	September- October	November- December
Maharashtra and parts of Gujarat	Early Kharif	February- March	April- May
	Kharif	May- June	July- August
	Late Kharif	August- September	October- November
	Rabi	October- November	December- January
Andhra Pradesh, Tamil Nadu, Karnataka	Early Kharif	February- April	April- June
	Kharif	May- June	July- August
	Rabi	September- October	November- December

Diseases and Plant Protection in Onion Farming

Onions suffer from a number of diseases caused by fungi, bacteria, nematodes and insects. Some major ones are as below:

Viral Diseases

Disease Name	Virus Name	Symptoms and Nature of Damage	Spread of Disease	Control Measures
Onion Yellow Dwarf	Onion Yellow Dwarf Virus	Infected leaves develop yellow streaks that spread progressively leading to yellow leaves Leaves curl and plants wilt Bulbs do not grow to full size although they are firm and solid	Spread mainly through aphids	Use of resistant variety Selecting healthy plant material for sowing Controlling aphids through inter-cropping Spraying insecticides like 0.1% Profenofos, 0.2% Carbosulfan or 0.1% Fipronil can control Aphids
Irish Yellow Spot	Irish Yellow Spot Virus	Leaves show lesions that maybe diamond or spindle-shaped They are straw-colored Sometimes they have distinct green center with yellow borders Flower stalks are infected in later stage	Thrips	Transplants must be checked for thrips invasion and diseases At least three years of crop rotation is advised for preventing this disease Crop stress must be avoided Controlling thrips is to extent seen effective in controlling the disease.

Fungal Diseases

Disease Name	Causative Agent	Symptoms and Nature of Damage	Spread	Control Measures
Damping Off	Water soaking	Seedlings topple after emerging from soil It occurs at ground or below ground level Infected tissues appear soft and water soaked		Planting onion on a raised bed Treating the seeds with Thiram Drenching the nursery beds with 0.2% Captan or 0.1% Carbendazim or 0.3% Copper oxychloride
Stemphylium blight	Stemphylium vesicarium	Yellow to orange colored small flecks develop in the middle of the leaf The flecks spread to form elongated, spindle shaped to ovate, diffused spots They are surrounded by characteristic pink margin The spots progress from the tip to the base of the leaves They coalesce into extended patches		Spaying fungicides like 0.25% Mancozeb, 0.1% Tricyclazole, 0.1% Hexaconazole or 0.1% Propiconazole every 10-15 days interval starting from 30 days after transplanting or as soon as disease appears.
Purple Blotch	Alternaria  porri	They begin as small, elliptical lesions Lesions turn purplish-brown progressively They are surrounded by chlorotic margins Lesions begin at tip of older leaves They girdle the leaves making it fall off		Spaying fungicides like 0.25% Mancozeb, 0.1% Tricyclazole, 0.1% Hexaconazole or 0.1% Propiconazole every 10-15 days interval starting from 30 days after transplanting or as soon as disease appears.
Anthracnose (twister disease)	Colletotrichum gleosporiodes	Abnormal elongation of the neck Twisting, curling of leaves Water-soaked lesions that are pale yellow in color appear initially on leaf blades Black-colored structures appear around the centre. These are at a slight elevation Leaves shrivel, droop and finally wither away		Avoid water logging Plant onions on raised beds Treat soil with 0.2% benomyl 0.25% foliar spray of Mancozeb

Insect Diseases

Pest Name	Identification	Symptoms and Nature of Damage	Control Measures
Thrips (Thrips tabaci)	Adult thrips are yellow to black colored with 4 wings Immature thrips have white color body with no wings	Infestation caused upto 45 days after transplanting Leaves twist and curl Silvery, white patches on leaves Plants are blemished and white in severe cases	Intercropping with maize or sugarcane is one of the best methods of controlling thrips Insecticides must be sprayed when the thrips population cross 30 per plant
Eriphyid mites	Microscopic mites that pinkish to purple in color Difficult to identify with naked eye unless there ia a colony of the mites	Yellow mottling along the edge of leaves Leaves do not open completely Plants curl up	0.05% Sulphur spray 0.2% dicofol as soon as symptoms appear and then every 15 days thereon

Onion Harvesting

Onion harvesting is done when the still green tops start drooping. The plants are gently pulled out from the soil. However, 10-15 days before harvesting irrigation of the field is stopped. The crop is also sprayed with 1000 ppm carbendazim 30 days before harvest. This helps increase the shelf-life of the crop. The bulbs are cleaned and dried in shade for 4 days.

Onion Grading

After harvesting, the bulbs are graded according to their size as A (more than 80mm), B (50-80 mm) and C (30-50 mm). In India, this is done manually as well as via machines.

Onion Storage

Generally, onion bulbs harvested in rabi season have better shelf-life than kharif. Light red onion varieties have better storage potential than the dark red varieties. They are stored in jute bags or wooden baskets. They are also stored in netted bags. This is important because onions emit gas which if may lead to rotting if not allowed to escape. Optimum temperature for storage is 30-35˚C with 65-70% relative humidity.

Cold storage increases the shelf life. The loss of crop after storing in cold for six months has been found to be 5%. However, extremely low temperature (less than -2⁰C) can lead to freezing injury. A high temperature can cause rotting. A gradual decrease of temperature prevents microbial decay.

Conclusion

In the recent years India faces a shortage in onion on a yearly basis and this triggers price rise. Therefore, onion cultivation can be a huge money making agribusiness.

Reference

1. http://apeda.gov.in/apedawebsite/SubHead_Products/Onions.htm
2. https://en.wikipedia.org/wiki/Onion
3. http://www.centerchem.com/Products/DownloadFile.aspx?FileID=6784
4. http://dogr.res.in/index.php/en/onion
5. http://agritech.tnau.ac.in/horticulture/horti_vegetables_small%20onion.html
6. http://www.krishisewa.com/crop_system/varieties/vegetable-varieties/596-varieties-onion.html
7. http://vikaspedia.in/agriculture